Overview of Continuous Emissions Monitoring Systems (CEMS)

A CEMS comprises the necessary equipment to determine the emission rate or concentration of a particulate matter or gas. Facilities utilise CEMS to collect, report, and record the emissions data continuously. Components of continuous emissions monitoring systems typically include emissions analysers, sample probes, pumps, calibration gases, sample conditioners, etc. It is easy to get one because there is a variety of a CEMS combination available due to its custom-made nature.

Overview of Continuous Emissions Monitoring Systems (CEMS)

Applications of CEMS

Continuous emissions monitoring systems are useful in applications of optimization and process control. These also measure the concentrations of a variety of pollutants and other elements like water, nitrogen dioxide, oxygen, hydrogen sulfide, carbon dioxide, total hydrocarbon, and nitrogen monoxide.

CEMS are used in a wide range of applications, such as:

  • Commercial and industrial boilers
  • Brick and glass manufacturers
  • Waste incineration plants
  • Pulp and paper facilities
  • Chemical manufacturers
  • Nitric acid plants
  • Gas turbines
  • Wastewater treatment plants
  • Pharmaceutical facilities
  • Aluminium and steel smelters
  • Refineries
  • Power plants


A continuous emissions monitoring system of the gas analyzer may deploy a detection technology like the following:

  • Flame ionization detection. This analyses the ions from the hydrogen flame during the combustion of emissions.
  • Chemiluminescence. This one measures the nitrogen oxides and determines the light intensity brought on by an ozone and nitric oxide reaction.
  • Fourier Transform Infrared spectroscopy. It is useful for the analysis of various gases. The FTIR also measures the emission sources of the varying infrared spectrum.
  • Pulsed fluorescence. This process entails exposing gas to UV radiation and measures the fluorescence that is released while the gas absorbs the ultraviolet light.

System Integration

Effective integration of continuous emissions monitoring systems begins with the best practices of the basic design. Careful planning results in comprehensive data capture and long-term use, factoring in system siting, materials compatibility, minimal maintenance, ease of use, source constituents, and redundancy.

Maintainability and redundancy of the system are crucial factors in CEMS, particularly during periodic testing. The fundamental design of the CEMS should be robust and simple. Also, the parameters of the sampling system essential in measuring the condition and performance of sample lines, probes, pumps, and filters must be accessible.


An extractive monitoring system is a common form of CEMS. The initial step in the measurement of the extractive monitoring system involves taking out a sample of gas emissions. The sample goes through a filtering and conditioning process before being transferred to the gas analysers. This is to eliminate moisture or particulate matter that could clog conduits, damage instrumentation, or hamper precise sensing of the pollutants.

The analysers measure the gas concentration and transfer it to a data acquisition system to record and collect emission data. The main functionality of the CEMS in terms of data acquisition system is to document measurements. Data acquisition systems are able to generate reports and display data to assess compliance and evaluate system parameters in real-time.

To ensure effective and correct emissions data, the CEMS requires regular calibration and quality checks. Having continuous emissions monitoring systems in your facility means you are complying with air-quality guidelines. Sometimes, as self-regulation, a company will install a CEMS to gather data procedures as part of its monitoring system. If you need to install CEMS, make sure to have a plan and conform to the rules when using a system that requires continuous use.

Author Bio:

Julian Carter is a farmer of words in the field of creativity. She is an experienced independent content writer with a demonstrated history of working in the writing and editing industry.  She is a multi-niche content chef who loves cooking new things.